Abrading implement

ABSTRACT

AN ABRASIVE CONE ASSEMBLY COMPRISING A MANDREL AND AN EXPENDABLE CONE TIP. THE ROTARY DRIVING CONNECTION BETWEEN THE ELEMENTS INCLUDES COMPLEMENTARY PROJECTING AND RECESSED PORTION ALLOWING A CLOSED COUPLED CONNECTION THEREBETWEEN, AND FEATURES A PROJECTING PIN ON THE MANDREL PROVIDING ELONGATED CENTRAL BEARING SUPPORT IN THE CONE.

Oct. 26, 1971 H. E. COOK ABRADING IMPLEMENT Filed July 18, 1969l/VVE/VTOI? HERBERT E. COOK 3,614,845 ABRADTNG IMPLEMENT Herbert 13.Cook, 98 W. Floyd Ave, Dayton, flhio 45415 Filed July 155, 1969, Ser.No. 842,997 Int. Cl. 324d 17/00 U.S. Cl. 51-358 9 Claims e... mi

ABSTRAJCT UP THE DISCLUSURE BACKGROUND OF THE INVENTION This inventionrelates to abrasive cone assemblies and in particular to means formounting a replaceable abrasive cone member to a work tool or mandrel.

Devices of the class described are mounted in rotary power tools andperform chamfering and like operations in connection with drilled holes.The mandrel is a permanent or continuing part of the assembly and isadapted to be held in a tool chuck. The abrasive cone member comprises amoldable body having a covering of abrasive cloth. It is joined to themandrel for unison rotation but is preferably made separable therefromfor ease of replacement. In use, the abrasive cloth becomes worn and itis the usual practice to consider the cone member including the body andabrasive covering to be expendable. In this manner the working surfaceof an abrasive cone assembly can be renewed at less cost and with lesstrouble than were the entire assembly including the mandrel to bereplaced. A superficially worn cone member is detached bodily from themandrel and replaced by a new member from a supply of pre-assembledunits. When recovery or salvage is economically feasible, worn abrasivecoverings are stripped from discarded cone members and the molded bodiesbeing thus made available for reuse. The general application of abrasivecone assemblies is one in which continuing use of a tool involvesfrequent replacement of the cone tips. Speed and ease of attaching anddetaching of the cone tips accordingly are factors of importance, as arereliability and the defining and maintaining of a precise, axialdisposition of the cone tip relatively to the mandrel. Low cost is ofcourse an important objective in view of the included concept ofexpendability. In the prior art these objectives have been onlyinconsistently or in part realized. For example, it has been known toprovide a threaded connection between the mandrel and cone tip. Thismakes for a secure connection but is costly and replacement cannot bedescribed as quick and easy. Designs of greater attachment anddetachment facility have been susceptible to twisting and distortingforces and are not securely mounted or tend to become misaligned in use.

SUMMARY In accordance with the present invention, an abrasive coneassembly achieves ends desirable in a device of its class to a greaterextent than has been known heretofore, and it is an object of theinvention to provide a device so characterized. In the illustrativeembodiment of the invention the mandrel and moldable body haveinherently interengageable portions which are made to interfit with oneanother by a simple axial approaching motion of the parts. A relativelyprojecting pin on the mandrel deeply penetrates the body. It provides acentral bearing inhibit- 3,bM-,M5 Patented @ct. 26, 1971 ingmisalignment. Also it has a friction-vacuum fit in, the body obviatingaccidental loss of the cone tip from the mandrel. The connection readilyyields, however, to an applied axial pull for simplified removal of aworn cone. According to a further feature of the invention the rotarydriving connection between the parts is entirely contained within themandrel. The result is a compact, close coupled device in which thedriving connection is fully supported against the effects of torsionaland angularly deflecting forces.

Other objects and structural details of the invention will appear fromthe following description, when read in connection with the accompanyingdrawings, wherein:

FIG. 1 is a view in perspective of an abrasive cone assembly inaccordance with the illustrated embodiment of the invention, shown inthe course of application to the work;

FIG. 2 is a view in perspective, showing the mandrel and cone elementsof the assembly in a separated relation;

FIG. 3 is a view in front elevation of the inner or attaching face ofthe cone element;

FIG. 4 is a view like FIG. 3, showing the outer or attaching face of themandrel element;

FIG. 5 is a view in side elevation of an abrasive cone assembly inaccordance with the illustrated embodiment of the invention;

FIG. 6 is a view in longitudinal section of the abrasive cone assembly;and

FIG. 7 is a top plan view of an abrasive cloth blank which together witha moldable cone body to which the formed blank is applied comprises thecone element.

In its illustrated embodiment, the invention deals with an abrasive coneassembly. It will be evident, however, that since the invention isprincipally concerned with interengaging means between a mandrel or Workspindle and an extended working end thereof the exact character of thetool involved is unessential.

As shown in FIG. 1, an abrasive cone assembly according to theillustrated embodiment comprises a mandrel 10, and, as a separable workcontacting extension thereof, a cone element 20. The mandrel 10 is madeof tool steel or the like to be wear resistant and substantiallyunaffected by operational stresses. A cylindrical body portion 11thereof is externally knurled so that the mandrel may be moreeffectively gripped in handling and in inserting it in and withdrawingit from the chuck of a power tool. A reduced diameter shank portion 12extends from one end of body 11 and is adapted to be received in andheld by chuck means 13 of a power tool. In the opposite direction frombody 11, the mandrel progressively increases in diameter and terminatesin a relatively broad flange 14. The cone element 20 projects fromflange 14 as a working tip of the mandrel. It is suitably abrasivecovered and is particularly adapted for the chamfering of small diameterholes. As shown, a work piece 15 provides a series of holes 16.Introduced axially into successive openings 16, the cone 20, whenrotated, forms a chamfer 17 thereon having an angularity determined byand corresponding to the angularity of the cone element.

The flange 14. defines an outer end of the mandrel 10, more particularlyrepresented by a flat, transverse face 18 (FIGS. 2 and 4). Centrallythereof the face 18 is formed with a shallow, circular recess 19. Thebottom of recess 19 is in turn recessed, in this instance by a moredeeply cut non-circular recess 21. In the illustrated instance recess 21has a square configuration. Occupying an upright position within thesquare recess 21 is a pin 22. The latter forms an integral part ofmandrel ltl and is coaxially disposed of the mandrel and of recesses 19and 21. Having a diameter small in relation to transverse dimensions ofsquare recess 21, the pin is spaced from the walls thereof. It is,moreover, relatively elongated, extending through and beyond recess 21,recess 19 and through and beyond the transverse plane of face 18. Theouter end of the pin 22 accordingly is in a relatively projectingrelation to the outer end of mandrel 10.

The cone element 20 is comprised of a molded body 23 made of aresilient, deformable material. The body 23 has a cone shape. Theconical, sloping sidewall thereof is covered by a layer 24 of abrasivecoated cloth material. While the layer 24 may initially have variousconfigurations it is in the illustrated instance, as shown in FIG. 7,normally comprised of a fiat disc of flexible, cloth-like material. Asegment of the disc is cut out to define curvilinear, spaced edges 25and 26 of complementary curvature. One side of the disc is coated withabrasive particles. Upon adhesive being applied to the uncoated side,the disc is applied to a body 23 centrally thereof. It is pressed aboutthe body to conform to the conical shape thereof, and, in the process,the complementary edges 25 and 26 are brought to an interfittingrelation to define a butt joint 27. The abrasive coated layer 24 ofmaterial adheres to the body 23 and forms a unitary part thereof.

The molded body 23 has a short length cylindrical portion 28. A portionof the body presented forwardly thereof has the described conicalconfiguration and mounts the abrasive layer 24. At what may beconsidered an inner end thereof the portion 28 terminates in an inwardlypresented transverse face 29. A central, smaller diameter portion offace 29 is relatively projecting to define a shoulder lamination 31 ofcircular form. From the middle of lamination 31 further extends a squareshaped projection 32. A central bore or hole 33 is in the center ofprojection 32, opening through the outer end thereof, and extendsthrough and beyond lamination 31, face 29 and relatively deeply intobody 23 toward the apex thereof. The face 29 of cone element 20 isadapted to make a flush, contacting engagement with face 18 of mandrel10. The circular lamination 31 on the cone element is adapted to bereceived within circular recess 19 of the mandrel. Square shapedprojection 32 of the cone is adapted to be received in mandrel recess21. The hole 33 accommodates entry of pin 22. The lamination 31 andsquare shaped projection 32 have a reasonably close but not tightfitting engagement in their respective recesses 19 and 21 in themandrel. Hole 33, however, is slightly undersize in diameter relative topin 22.

Use of an abrasive cone assembly is, as previously described,substantially in accordance with the illustration of FIG. 1. Thesubstitution of cone elements in the assembly is substantially asindicated in FIG. 2. In a relative approaching motion, the face 29 ofthe cone element is brought toward a seating relation to face 18 of themandrel. In the process, pin 22 is caused to penetrate hole 33 and ispressed axially therein. The material of body 23 is, in the region ofhole 33, slightly deformed thereby and responds with a reactant grippingpressure upon the pin. The relative approaching motions of the cone andmandrel elements is continued, guided by the pin 22 and by entrance ofprojection 32 into recess 21 and by entrance of lamination 31 intorecess 19. The depth of hole 33, and the relative lengths of lamination31 and projection 32 is such to allow relative approaching motion of theparts to continue until face 29 seats upon face 1 8 at which time thelamination 31 and projection 32 are fully accommodated in theirrespective recesses. With the parts so assembled, the interengagement ofsquare shaped projection 32 in recess 21 defines a rotary drivingconnection between the mandrel and cone tip. Lamination 31, in additionto guiding the cone tip to a proper seat upon the mandrel positions itin a lateral sense, assisting in maintaining a constant axial alignmentof the mandrel and tip. The pin 22 further acts as an axial guide andprovides an elongated center bearing for the body 23. Forces developedin use tending to tilt or to cock the cone element are resisted by thepin 22. Still further, the pin 22,

since it is gripped by the resilient deformable material of body 23,prevents accidental detachment of the cone from the mandrel. In handlingof the abrasive cone assembly, therefore, and in its application to andwithdrawal from the work, the frictional fit of the molded body upon pin22 holds the elements in an assembled relation.

Detachment of a worn cone member from the mandrel is accomplished by anaxial pulling or separating motion applied to the cone element while themandrel continues to be held. The close fit of pin 22 in hole 33 createssuction as well as friction forces yieldingly resisting detachment ofthe cone member.

The diameter of face 29 on the cone element is somewhat larger than thediameter of mandrel face 18. There is created thereby, in the assembledrelation of the parts, a narrow annular shoulder on the cone elementfacilitating its gripping for removal.

The absence of an overlap in the abrasive covering 24 obviates problemsof uneven wear and insures the formation of true, uniform chamferedsurfaces. It will be understood, however, that any conventional methodsof mounting an abrasive cloth material to a moldable body may beutilized in the practice of this invention.

The rotary driving connection between the mandrel and cone element isfully contained within the mandrel. All portions of the moldable bodyare accordingly extensively supported either within the mandrel or bythe projecting pilot pin 22. Little or no unsupported resilientdeformable material is presented to be subject to twisting anddistorting forces. Further, the arrangement is one to make the coneassembly a compact, close coupled device providing direct axial backingfor the cone and improving the facility of use and handling of thedevice.

A preferred embodiment of the invention has been disclosed but it willbe evident that the invention has other applications, and, thatstructural modifications thereof are possible, and contemplated.

I claim:

1. An abrading implement, including a mandrel having an axiallyprojected pin in an outer end thereof, a moldable body having aninwardly presented face to seat against the said outer end of saidmandrel and formed to allow penetration thereof by said pin asubstantial distance beyond said face, said body beyond said face havingan outwardly presented abrasive covered portion, and interengageablemeans on the said outer end of said mandrel and on said face of saidbody comprising a rotary driving connection from said mandrel to saidbody, said moldable body being an expendable member detachable from saidmandrel by an axial pulling motion, said pin having a friction fittherein tending yieldingly to maintain said moldable body in an attachedposition, with said face thereon seating to the said other end of saidmandrel, said moldable body having a hole therein to receive said pin,said body being made of a resilient deformable material and said holehaving a diameter slightly under size relative to that of said pin.

2. An abrading implement according to claim 1, said hole opening at oneend through said face and terminating at its other end within theoutwardly presented portion of said body, said pin providing a centralbearing for said moldable body inhibiting tilting motions thereofrelative to said mandrel.

3. An abrading implement, including a mandrel having an axiallyprojected pin in an outer end thereof, a moldable body having aninwardly presented face to seat against the said outer end of saidmandrel and formed to allow penetration thereof by said pin asubstantial distance beyond said face, said body beyond said face havingan outwardly presented abrasive covered portion, and interengageablemeans on the said outer end of said mandrel and on said face of saidbody comprising a rotary driving connection from said mandrel to saidbody, said moldable body being aligned with said mandrel and serving asan axial extension thereof, said interengageable means on said body andsaid mandrel being interengaged by a relative approaching motion of saidmandrel and body guided by said pin and having a complementaryprojecting and recessed relationship to one another allowing the face ofsaid body a flush seating contact with the said outer end of saidmandrel, the inwardly presented face of said moldable body defining thebase of a cone, the conical portion of which begins adjacent to saidface and defines with said face an intermediate cylindrical portion ofminimal length, said moldable body having an axil hole to receive saidpin, said hole opening through said face and extending toward the apexof the cone, said pin being received therein in a manner to provideelongated central bearing support for said body, said body being made ofa resilient deformable material and said pin being oversized to have afriction fit in said hole.

4. An abrading implement, including a mandrel having an axiallyprojected pin in an outer end thereof, a moldable body having aninwardly presented face to seat against the said outer end of saidmandrel and formed to allow penetration thereof by said pin asubstantial distance beyond said face, said body beyond said face havingan outwardly presented abrasive covered portion, and interengageablemeans on the said outer end of said mandrel and on said face of saidbody comprising a rotary driving connection from said mandrel to saidbody, said interengageable means including a non-circular recess in thesaid outer end of said mandrel and a projection of correspondingconfiguration on the said face of said moldable body, said recess andsaid projection interfitting in response to a relative approachingmotion of said mandrel and said body guided by said pin, said pinprojecting from the bottom of said recess through and beyond thetransverse plane of the said outer end of said mandrel.

5. An abrading implement according to claim 4, characterized in thatsaid projection on the face of said body is centrally positionedthereon, said body being formed with an axial hole opening at one endthrough said projection and terminating within the outwardly presentedportion of said body to receive said pin in a manner to allow the faceof said body to seat on said mandrel and to provide through said pin acentral bearing for said body inhibiting relative tilting motionsthereof.

6. An abrading implement, including a mandrel having an axiallyprojected pin in an outer end thereof, a moldable body having aninwardly presented face to seat against the said outer end of saidmandrel and formed to alloW penetration thereof by said pin asubstantial distance beyond said face, said body beyond said face havingan outwardly presented abrasive covered portion, and interengageablemeans on the said outer end of said mandrel and on said face of saidbody comprising a rotary driving connection from said mandrel to saidbody, said interengageable means including a recess in the outer end ofsaid mandrel and complementary means on said face of said body adaptedto be received in said recess, said pin being based in said recess andspaced from side walls thereof, the said complementary means on saidface of said body being formed with a co axially disposing holefacilitating penetration of said body by said pin.

7. An abrading implement according to claim 6, wherein said pin is arelatively slender elongate member substantially uniform in crosssection over the major part of its length, said moldable body being madeof a resilient deformable material with said hole therein being formedin substantial correspondence with the pin but slightly undersize intransverse dimension for a utilizing of suction and friction forces toresist detachment of the body from the mandrel.

8. An abrading implement, including a mandrel having an axiallyprojected pin in an outer end thereof, a moldable body having aninwardly presented face to seat against the said outer end of saidmandrel and formed to allow penetration thereof by said pin asubstantial distance be yond said face, said body beyond said facehaving an outwardly presented abrasive covered portion, andinterengageable means on the said outer end of said mandrel and on saidface of said body comprising a rotary driving connection from saidmandrel to said body, said outer end of said mandrel being recessed in asurrounding relation to said pin, a portion of said face of said bodybeing projected to be accommodated in the said outer end of the mandreland said portion having a longitudinally extending hole receiving saidpin with a friction fit.

9. An abrading implement, including a mandrel having an axiallyprojected pin in an outer end thereof, a moldable body having aninwardly presented face to seat against the said outer end of saidmandrel and formed to allow penetration thereof by said pin asubstantial distance beyond said face, said body beyond said face havingan outwardly presented abrasive covered portion, and interengageablemeans on the said outer end of said mandrel and on said face of saidbody comprising a rotary driving connection from said mandrel to saidbody, said pin being a slender elongate member substantially uniform incross section over the major part of its length, said moldable bodybeing made of a resilient deformable material and being formed with acoaxially disposing hole facilitating penetration of said body by saidpin, said hole being formed in substantial correspondence with the pinbut slightly undersize in transverse dimension for a utilizing ofsuction and friction forces to resist detachment of the body from themandrel.

References Cited UNITED STATES PATENTS 2,958,166 11/1960 Foland 5l3582,581,567 1/1952 Wiley 5l-358 2,864,208 12/1958 Ringer 5l392 X 2,826,0143/1958 Field 5l190 3,129,541 4/1964 Field 5l380 X JAMES L, JONES, 111.,Primary Examiner

